When is an ad not an ad?

The most I found really interesting about this post this post published on Mobile Marketer was:

Promoted discoveryFinally one of my favorite ad products I am seeing the rise of is the third-party product review in ad units on news sites. It is the “Recommend” articles you see at the bottom of the page.

There are a couple of companies helping facilitate this, notably Outbrain and Mashable’s “lift” product.